Bone marrow stem cell applied in the canine veterinary clinics / Células tronco de medula óssea utilizadas na clínica veterinária canina

Cell therapy represents an old therapeutic practice initiated with the transfusion of whole blood in different clinical situations. There is now a breakthrough in the study of multipotent stem cell therapy because of its functionality in regeneration of tissues, which promotes attention of the scientific community. Bone marrow is one of the main sources of multipotent stem cells, composed by hematopoietic stem cells responsible for the renewal of the cellular components of the blood, and mesenchymal stem cells that aid in the regeneration of tissues. These cells have a strong potential for the treatment of several diseases, due their main characteristics such as high plasticity, capacity for self-renewal and immunomodulation. Although, there are many studies that show good results with the use of cell therapy as a form of treatment for several diseases, some studies still show inconclusive or unsatisfactory results. Therefore, the objective of this study was to review the application of bone marrow stem cells in the canine model since improvements on the knowledge of the technique are necessary to enable its applicability with safety and efficacy.(AU)

A terapia celular representa uma antiga prática terapêutica iniciada com a transfusão de sangue total em diferentes situações clínicas. Atualmente há um avanço no estudo da terapia com células-tronco mesenquimais por conta de sua funcionalidade na regeneração de tecidos, o que promove uma crescente atenção do meio científico. A medula óssea é uma das principais fontes de células-tronco multipotentes, no qual se encontram as células-tronco hematopoiéticas, responsável pela renovação dos componentes celulares do sangue, e as células-tronco mesenquimais que auxiliam na regeneração de tecidos. Essas células têm um forte potencial para o tratamento de diversas enfermidades, uma vez que possuem como principais características alta plasticidade, capacidade de auto renovação e imunomodulação. Apesar de haver muitos trabalhos que apresentam bons resultados com a utilização da terapia celular como forma de tratamento para diversas enfermidades, alguns estudos ainda demonstram resultados inconclusivos ou não satisfatórios, por isso, objetivou-se com este trabalho revisar a aplicação das células-tronco derivadas da medula óssea no modelo canino uma vez que é necessário melhorias sobre o conhecimento da técnica para que possibilite a sua aplicabilidade com segurança e eficácia.(AU)

Effects of ovariectomy on the secretory apparatus in the right atrial cardiomyocytes of middle-aged mice.

OBJECTIVE: The aim of the present study was to evaluate the effects of ovariectomy on the secretory apparatus of natriuretic peptides in right atrial cardiomyocytes. METHODS: Nine-month-old mice underwent bilateral ovariectomy or sham surgery. The blood exam of the ovariectomized mice showed results consistent with castrated females. Systolic blood pressure was measured after ovariectomy (9 mo of age) and at the moment of sacrifice (12 mo of age). Fragments of the right atrium were collected and prepared for electron microscopy examination. The following variables were quantified: the quantitative density and area of the natriuretic peptide granules, the relative volume of euchromatin in the nucleus, the number of pores per 10 µm of the nuclear membrane and the relative volumes of the mitochondria and Golgi complex. RESULTS: The cardiomyocytes obtained from ovariectomized mice indicated that the quantitative density and the area of secretory granules of natriuretic peptides were significantly lower compared with the sham-operated mice. Furthermore, there was a decrease in the relative volume of euchromatin, a lower density of nuclear pores, and lower relative volumes of the mitochondria and Golgi complex in the ovariectomized mice compared with the sham-operated mice. These findings suggest a pool with a low turnover rate, i.e., low synthesis and elimination of natriuretic peptides. CONCLUSION: A lack of estrogen caused hypotrophy of the secretory apparatus in right atrial cardiomyocytes that could explain the weak synthesis of natriuretic peptides in mice. Furthermore, one of the mechanisms of blood pressure control was lost, which may explain, in part, the elevated blood pressure in ovariectomized mice.

Effects of ovariectomy on the secretory apparatus in the right atrial cardiomyocytes of middle-aged mice

OBJECTIVE : The aim of the present study was to evaluate the effects of ovariectomy on the secretory apparatus of natriuretic peptides in right atrial cardiomyocytes. METHODS: Nine-month-old mice underwent bilateral ovariectomy or sham surgery. The blood exam of the ovariectomized mice showed results consistent with castrated females. Systolic blood pressure was measured after ovariectomy (9 mo of age) and at the moment of sacrifice (12 mo of age). Fragments of the right atrium were collected and prepared for electron microscopy examination. The following variables were quantified: the quantitative density and area of the natriuretic peptide granules, the relative volume of euchromatin in the nucleus, the number of pores per 10 μm of the nuclear membrane and the relative volumes of the mitochondria and Golgi complex. RESULTS: The cardiomyocytes obtained from ovariectomized mice indicated that the quantitative density and the area of secretory granules of natriuretic peptides were significantly lower compared with the sham-operated mice. Furthermore, there was a decrease in the relative volume of euchromatin, a lower density of nuclear pores, and lower relative volumes of the mitochondria and Golgi complex in the ovariectomized mice compared with the sham-operated mice. These findings suggest a pool with a low turnover rate, i.e., low synthesis and elimination of natriuretic peptides. CONCLUSION: A lack of estrogen caused hypotrophy of the secretory apparatus in right atrial cardiomyocytes that could explain the weak synthesis of natriuretic peptides in mice. Furthermore, one of the mechanisms of blood pressure control was lost, which may explain, in part, the elevated blood pressure in ovariectomized mice. .

A morphological analysis of the transition between the embryonic primitive intestine and yolk sac in bovine embryos and fetuses.

The yolk sac (YS) is the main source of embryonic nutrition during the period when the placenta has not yet formed. It is also responsible for hematopoiesis because the blood cells develop from it as part of the primitive embryonic circulation. The objective of this study was to characterize the transitional area between the YS and primitive gut using the techniques of light microscopy, transmission electron microscopy, and immunohistochemistry to detect populations of pluripotent cells by labeling with Oct4 antibody. In all investigated embryos, serial sections were made to permit the identification of this small, restricted area. We identified the YS connection with the primitive intestine and found that it is composed of many blood islands, which correspond to the vessels covered by vitelline and mesenchymal cells. We identified large numbers of hemangioblasts inside the vessels. The mesenchymal layer was thin and composed of elongated cells, and the vitelline endodermal membrane was composed of large, mono- or binucleated cells. The epithelium of the primitive intestine comprised stratified columnar cells and undifferentiated mesenchymal cells. The transitional area between the YS and the primitive intestine was very thin and composed of cells with irregular shapes, which formed a delicate lumen containing hemangioblasts. In the mesenchyme of the transitional area, there were a considerable number of small vessels containing hemangioblasts. Using Oct4 as a primary antibody, we identified positive cells in the metanephros, primordial gonad, and hepatic parenchyma as well as in YS cells, suggesting that these regions contain populations of pluripotent cells.